A lot of people think that homosexuality is a simple matter of genetics—if you have the so-called “gay gene,” well, you know the rest. In other words, gays and lesbians are just “born that way” and that’s that.

Increasingly, scientific research suggests there are multiple factors that might contribute to homosexual orientation—and they’re very different from one person to the next. The end result of all this variability is that different “kinds” or “types” of homosexuality probably exist.

This study focused specifically on exploring the potential origins of male homosexuality…Whereas most research in this area has treated gay men as a homogeneous group, the researchers leading this study instead looked at subgroups of gay men who differed based on their preferred anal sex role: “tops” (the insertive partner), “bottoms” (the receptive partner), and “versatile” (those who are open to switching roles).

…

Gay men with a bottom/versatile preference were less likely to be right-handed than tops—but tops and straight men did not differ when it came to which hand was dominant. This suggests that gay men’s anal sex role preferences are rooted, to some degree, in their biology.